1995 Accord Crank But No Start

I have a 1995 Accord that cranks (turns over) when I turn the key, but it won’t start. I bought a new battery but that didn’t fix it – same exact symptoms. I gave up and decided to have it towed to a mechanic. Now here’s the weird part: the mechanic was unable to reproduce. The car started every time every day for a week. Indeed, when I went to pick it up, it started right up. Something about the towing process (a large jostle?) temporarily made the issue un-reproducible.

But now, a week after picking it up, it’s happening again. I can’t start it (cranks but no start). I have no idea how to proceed because I’m afraid having it towed again will just waste money when the mechanic can’t reproduce.

Any tips on how to proceed or troubleshoot? Something I could hit with a hammer to temporarily get it going? I have basic tools but no access to a shop.

Edit: In case this helps someone else, here was the problem:

D4 light started blinking and error code indicated main relay under the steering wheel was bad. Replacing it seemed to fix it, but then the problem returned a few days later so that clearly wasn’t it. D4 started blinking again so I took it to a mechanic who did more advanced electronics diagnostics.

Mechanic determined that the ECM (main computer) was faulty. Mechanic also discovered that pounding ECM while cranking can get it to start. The ECM is located under the passenger seat floor up near the glovebox or thereabouts. Sure enough if I sat in the passenger seat and kicked the floor up under the glovebox with my feet while the engine was cranking it would start right up.